1. Field of the Invention
The present invention relates to a scanning probe microscope with displacement detecting mechanism that measures various pieces of physical-property information about surface topography, viscoelasticity or the like of a sample by scanning the sample surface with the probe put in proximity thereto, and to a scanning probe microscope having the same.
2. Description of the Related Arts
As well known, the scanning probe microscope (SPM) is known as an apparatus for measuring a microscopic region of a sample, such as of metal, semiconductor, ceramic, resin, polymer, Bio material or insulator, and observing the sample as to its physical-property information of viscoelasticity, etc. or surface topography.
Of the scanning probe microscopes, there is well known a type having a cantilever in an elongate form having a reflection surface, a cantilever holder supporting the cantilever at one end, a light source for emitting light and a light receiver for receiving the light irradiated from the light source (see JP-A-2000-346784, for example).
With this structure, when light is emitted from the light source to a reflection surface, the light reflected by the reflection surface is to arrive at the light receiver. In such a case, if the cantilever has a deflection due to a concavo-convex of the sample, there occurs a deviation of arrival point to the light receiver. For this reason, by measuring such arrival points, the sample can be measured for its concavo-convex form.
Here, if a point to measure is specified by conducting an initial observation prior to a detailed measurement of the sample, detailed measurement can be proceeded with efficiency. For this purpose, an objective lens and an illumination system are arranged above or below the sample or the cantilever, to thereby obtain an optical image of the sample. Due to this, sample-surface scratches, for example, are observed to specify a point to measure.
However, where an objective lens and an illumination system are arranged above or below the sample or the cantilever in order to enhance the efficiency of measurement, less space is available in arranging the light source and the light receiver. The light from the light source could not be irradiated vertically to the reflection surface from above. In such a situation, it can be considered to obliquely irradiate the light from the light source to the reflection surface.
However, with mere oblique irradiation, the light from the light source impinges upon those elements of the objective lens, the illumination system, the cantilever holder or the base integrally formed with the cantilever, thus being obstructed from traveling. Due to this, the light could not properly arrive at the reflection surface, the light receiver or the like, thus raising a problem of making the measurement itself difficult to perform.